目的探讨同型半胱氨酸(homocysteine,Hcy)和脑微出血(cerebral microbleeds,CMB)的关系。方法检索Pubmed、Embase、Cochrane图书馆、中国知网和万方数据库从建库至2025-4-12发表的有关CMB与Hcy相关性的研究,采用R语言软件进行系统回顾...目的探讨同型半胱氨酸(homocysteine,Hcy)和脑微出血(cerebral microbleeds,CMB)的关系。方法检索Pubmed、Embase、Cochrane图书馆、中国知网和万方数据库从建库至2025-4-12发表的有关CMB与Hcy相关性的研究,采用R语言软件进行系统回顾和荟萃分析。计算回归模型的标准平均差(standard mean deviation,SMD)及OR值的95%CI作为合并效应的指标。采用Egger检验评估发表偏倚,并对存在显著异质性和发表偏倚的文献进行亚组分析。结果共纳入132篇文献。Meta分析结果显示,有CMB组Hcy水平高于无CMB组(SMD=0.90,95%CI:0.56~1.25,P<0.01),重度CMB组Hcy水平高于中度CMB组,中度CMB组高于轻度组(均P<0.01)。深部/幕下CMB组及混合CMB组患者Hcy水平较脑叶CMB患者高(P<0.05,P<0.01)。不同研究人群亚组分析显示,有CMB组Hcy水平仍较无CMB组高(均P<0.01)。单因素相关分析及多因素回归分析结果显示Hcy水平与CMB的发生呈显著正相关(分别COR=0.2648,95%CI:0.0729~0.4378,P=0.007;OR=1.4888,95%CI:1.0888~2.0359,P=0.012)。多因素回归分析未发现Hcy与CMB严重程度间具有相关性。结论Hcy可能是CMB发生的独立危险因素,提示高Hcy血症可能是早期预防和治疗CMB的重要靶点,完善Hcy水平检测及早期干预Hcy水平对心脑血管疾病的预防和早期治疗可能具有重要意义。展开更多
目的:分析伴有皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosomal dominant arteriopathy with the subcortical infarcts and leukoencephalopathy,CADASIL)患者的临床和影像学特征。方法:收集2013年1月至2018年1...目的:分析伴有皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosomal dominant arteriopathy with the subcortical infarcts and leukoencephalopathy,CADASIL)患者的临床和影像学特征。方法:收集2013年1月至2018年12月在中南大学湘雅医院通过基因确诊的CADASIL患者12例,回顾性分析其临床表现、危险因素、MRI影像学特征和Notch3基因突变。结果:12例患者年龄为(47.25±9.49)岁,临床表现以认知障碍(75%)和脑卒中事件(58.3%)最常见,2例表现为脑出血。合并偏头痛少见(25%)。MRI均存在累及脑室旁和深部白质的脑白质高信号(white matter hyperintensities,WMH)和腔隙及血管周围间隙(perivascular spaces,PVS)扩大。WMH主要累及额顶叶(100%)、颞叶(83.3%)、外囊(66.7%)、枕叶(41.6%)、胼胝体(41.6%)和颞极(33.3%);腔隙主要累及额叶(91.6%)、顶叶(83.3%)、颞叶(66.7%)、基底节区(66.7%)、脑干(41.6%)、枕叶(33.3%)、小脑(8.3%);扩大的PVS均位于基底节区(100%),部分累及皮层下(45.4%)。脑出血患者WMH程度较轻(Fezakas评分为1～2分),且外囊无受累。16.7%患者存在颅内大动脉狭窄。12例患者中共检测到8种不同的Notch3基因突变,位于6号外显子的c.1013G>C p.(Cys338Ser)为CADASIL新的致病突变。结论:本组以脑出血为表现的患者脑白质病变较轻,基因型亦有特异性,其临床表型可能与影像学、基因表型相关。展开更多
The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping...The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping is the primary method to enhance the reaction characteristics of calcium-based materials over multiple cycles.In particular,co-doping with variable-valence metal oxides(VVMOs)can effectively increase the oxygen vacancy content in calcium-based materials,significantly improving their cyclic reaction characteristics.However,there are so numerous VVMOs co-doping schemes that the experimental screening process is complex,consuming considerable time and economic costs.Density functional theory(DFT)calculations have been widely used to reveal the impact of metal oxide doping on the cyclic reaction characteristics of calcium-based materials,with calculation results showing good agreement with experimental conclusions.Nevertheless,there is still a lack of research on utilizing DFT to screen calcium-based materials,and a systematic research methodology has not yet been established.In this study,a systematic DFT-based screening methodology for calcium-based materials was proposed.A series of key parameters for DFT calculations including CO_(2)adsorption energy,oxygen vacancy formation energy,and sintering resistance were proposed.Furthermore,a preliminary mathematical model to predict the CaL TCES and CO_(2)capture performance of calcium-based materials was introduced.The aforementioned DFT method was employed to screen for VVMOs co-doped calcium-based materials.The results revealed that Mn and Ce co-doped calcium-based materials exhibited superior DFT-predicted reaction characteristics.These DFT predictions were validated through experimental assessments of cyclic thermochemical energy storage,CO_(2)capture,and relevant characterization.The outcomes demonstrate a high degree of consistency among DFT-based predictions,experimental results,and characterization.Hence,the DFT-based screening methodology for calcium-based materials proposed herein is a viable solution,poised to offer theoretical insights for the efficient design of calcium-based materials.展开更多
Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,ow...Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,owing to the mismatch in the coefficient of thermal expansion(CTE)between the joints and chip,the high Young's modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules,which increases the susceptibility of sintered joints to cracking,thereby leading to potential failure.This study developed a facile approach to synthesizing bayberry-like Ag microparticles(AgMPs)through the in situ assembly of silver nanorods,resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface.These particles exhibited a high specific surface area of 2.5389 m^(2)·g^(-1),which enhanced theirsintering activity,enabling sintering to occur at 149.7℃.Furthermore,the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste,thereby lowering the Young's modulus of the joints.The small grain size and intricate internal substructure of the joints yielded high shear strength,which reached112.50 MPa at 250℃.The Young's modulus could be adjusted,and the pores provided by the AgMPs maintained the Young's modulus within a low range(15.11-29.61GPa),effectively mitigating thermal stress.These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging.展开更多
文摘目的探讨同型半胱氨酸(homocysteine,Hcy)和脑微出血(cerebral microbleeds,CMB)的关系。方法检索Pubmed、Embase、Cochrane图书馆、中国知网和万方数据库从建库至2025-4-12发表的有关CMB与Hcy相关性的研究,采用R语言软件进行系统回顾和荟萃分析。计算回归模型的标准平均差(standard mean deviation,SMD)及OR值的95%CI作为合并效应的指标。采用Egger检验评估发表偏倚,并对存在显著异质性和发表偏倚的文献进行亚组分析。结果共纳入132篇文献。Meta分析结果显示,有CMB组Hcy水平高于无CMB组(SMD=0.90,95%CI:0.56~1.25,P<0.01),重度CMB组Hcy水平高于中度CMB组,中度CMB组高于轻度组(均P<0.01)。深部/幕下CMB组及混合CMB组患者Hcy水平较脑叶CMB患者高(P<0.05,P<0.01)。不同研究人群亚组分析显示,有CMB组Hcy水平仍较无CMB组高(均P<0.01)。单因素相关分析及多因素回归分析结果显示Hcy水平与CMB的发生呈显著正相关(分别COR=0.2648,95%CI:0.0729~0.4378,P=0.007;OR=1.4888,95%CI:1.0888~2.0359,P=0.012)。多因素回归分析未发现Hcy与CMB严重程度间具有相关性。结论Hcy可能是CMB发生的独立危险因素,提示高Hcy血症可能是早期预防和治疗CMB的重要靶点,完善Hcy水平检测及早期干预Hcy水平对心脑血管疾病的预防和早期治疗可能具有重要意义。
文摘目的:分析伴有皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosomal dominant arteriopathy with the subcortical infarcts and leukoencephalopathy,CADASIL)患者的临床和影像学特征。方法:收集2013年1月至2018年12月在中南大学湘雅医院通过基因确诊的CADASIL患者12例,回顾性分析其临床表现、危险因素、MRI影像学特征和Notch3基因突变。结果:12例患者年龄为(47.25±9.49)岁,临床表现以认知障碍(75%)和脑卒中事件(58.3%)最常见,2例表现为脑出血。合并偏头痛少见(25%)。MRI均存在累及脑室旁和深部白质的脑白质高信号(white matter hyperintensities,WMH)和腔隙及血管周围间隙(perivascular spaces,PVS)扩大。WMH主要累及额顶叶(100%)、颞叶(83.3%)、外囊(66.7%)、枕叶(41.6%)、胼胝体(41.6%)和颞极(33.3%);腔隙主要累及额叶(91.6%)、顶叶(83.3%)、颞叶(66.7%)、基底节区(66.7%)、脑干(41.6%)、枕叶(33.3%)、小脑(8.3%);扩大的PVS均位于基底节区(100%),部分累及皮层下(45.4%)。脑出血患者WMH程度较轻(Fezakas评分为1～2分),且外囊无受累。16.7%患者存在颅内大动脉狭窄。12例患者中共检测到8种不同的Notch3基因突变,位于6号外显子的c.1013G>C p.(Cys338Ser)为CADASIL新的致病突变。结论:本组以脑出血为表现的患者脑白质病变较轻,基因型亦有特异性,其临床表型可能与影像学、基因表型相关。
基金supported by the National Natural Science Foundation of China(52276204 and U22A20435)。
文摘The reaction characteristics of calcium-based materials during calcium looping(CaL)process are pivotal in the efficiency of CaL thermochemical energy storage(TCES)and CO_(2)capture systems.Currently,metal oxide doping is the primary method to enhance the reaction characteristics of calcium-based materials over multiple cycles.In particular,co-doping with variable-valence metal oxides(VVMOs)can effectively increase the oxygen vacancy content in calcium-based materials,significantly improving their cyclic reaction characteristics.However,there are so numerous VVMOs co-doping schemes that the experimental screening process is complex,consuming considerable time and economic costs.Density functional theory(DFT)calculations have been widely used to reveal the impact of metal oxide doping on the cyclic reaction characteristics of calcium-based materials,with calculation results showing good agreement with experimental conclusions.Nevertheless,there is still a lack of research on utilizing DFT to screen calcium-based materials,and a systematic research methodology has not yet been established.In this study,a systematic DFT-based screening methodology for calcium-based materials was proposed.A series of key parameters for DFT calculations including CO_(2)adsorption energy,oxygen vacancy formation energy,and sintering resistance were proposed.Furthermore,a preliminary mathematical model to predict the CaL TCES and CO_(2)capture performance of calcium-based materials was introduced.The aforementioned DFT method was employed to screen for VVMOs co-doped calcium-based materials.The results revealed that Mn and Ce co-doped calcium-based materials exhibited superior DFT-predicted reaction characteristics.These DFT predictions were validated through experimental assessments of cyclic thermochemical energy storage,CO_(2)capture,and relevant characterization.The outcomes demonstrate a high degree of consistency among DFT-based predictions,experimental results,and characterization.Hence,the DFT-based screening methodology for calcium-based materials proposed herein is a viable solution,poised to offer theoretical insights for the efficient design of calcium-based materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52075125 and 52105331)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515010591)Shenzhen Science and Technology Innovation Committee(Nos.JCYJ20210324124203009,JSGG20201102154600003,GXWD20231130103814001,GXWD20220721182229001)
文摘Silver paste is widely used in power electronics as a die-attach material owing to its low-temperature sinterability,high melting point,and excellent electrical and thermal conductivities in sintered joints.However,owing to the mismatch in the coefficient of thermal expansion(CTE)between the joints and chip,the high Young's modulus of sintered silver hinders the mitigation of the high thermal stress generated during the operation of power modules,which increases the susceptibility of sintered joints to cracking,thereby leading to potential failure.This study developed a facile approach to synthesizing bayberry-like Ag microparticles(AgMPs)through the in situ assembly of silver nanorods,resulting in a uniform distribution of nanoscale structures and mesopores on the particle surface.These particles exhibited a high specific surface area of 2.5389 m^(2)·g^(-1),which enhanced theirsintering activity,enabling sintering to occur at 149.7℃.Furthermore,the porous structure of the AgMPs effectively reduced the density of joints formed by sintering AgMP paste,thereby lowering the Young's modulus of the joints.The small grain size and intricate internal substructure of the joints yielded high shear strength,which reached112.50 MPa at 250℃.The Young's modulus could be adjusted,and the pores provided by the AgMPs maintained the Young's modulus within a low range(15.11-29.61GPa),effectively mitigating thermal stress.These new bayberry-like porous AgMPs offer a promising option for die-attach materials in electronic packaging.
